If $a + 2b + c = 1$ and $3x + 5y + 9z = -7$, what is $-6a - 27z - 9x - 6c - 15y - 12b$ ?
$= -6a - 12b - 6c - 9x - 15y - 27z$ $= (-6) \cdot (a + 2b + c) + (-3) \cdot (3x + 5y + 9z)$ $= (-6) \cdot (1) + (-3) \cdot (-7)$ $= -6 + 21$ $= 15$